This project will investigate the role of the mother in providing carnitine to the infant during pregnancy and lactation, using the rat as a model. The specific goals are to: 1. determine the extent to which the fetus and neonate are dependent upon the maternal supply of carnitine. 2. determine whether malnutrition affects the ability of the mother to synthesize the carnitine precursor trimethyllysine and/or alter maternal carnitine level in milk and tissues. Carnitine has been suggested to be an essential nutrient for neonates, particularly in the premature. This is based upon data concerning premature infants on TPN, as well as for the fact that lipids are the major fuel source for the neonatal human, as well as for the neonatal rat. Carnitine deficiency syndromes for infants have been described which, in some cases, have been responsive to dietary carnitine. It has been hypothesized that some of these defects may be attributed to a defect in carnitine biosynthesis. Evidence exists that the last enzyme in the pathway, Gamma-butyrobetaine hydroxylase, does not reach adult levels until after birth. However, the physiological significance of this is uncertain. Additionally, the extent to which the fetus and/or neonate is dependent upon the mother as a source of carnitine is unknown. However, it has been noted that maternal milk is a concentrated source of carnitine. The first half of the proposed work will determine the importance of the maternal supply of carnitine, throughout the nursing period. Female rats will be offered water containing tritium or [14C] labelled carnitine. This experiment will determine the quantity of carnitine passed on to the fetus in utero, given the neonate in nurse milk, and synthesized de novo by the fetus and neonate. The data from this model will provide insight into how other mammalian systems function and aid in the determination of which age groups would benefit most from dietary carnitine supplementation. The second experiment will determine the effects of feeding a lysine-deficient diet upon trimethyllysine biosynthesis and tissue carnitine and trimethyllysine in the female rat during pregnancy. Milk carnitine will also be measured. This study will have importance in terms of optimal growth and possible effects on fatty acid oxidation for both the mother and the neonates.